Word: plasm
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...This lasts for only some .00001 sec., but large protein molecules may be broken up, carbon dioxide and hydrogen given off, and water molecules in the cell oxidized to hydrogen peroxide. The cell may then sicken and die. If it is a cell in the reproductive germ plasm, a mutation or hereditary change may occur...
...extremes of temperature produce such mutations as abnormal eyes, queer-shaped wings and bald thoraxes in Drosophila melanogaster, the little fruit fly made famous by the genetic researches of Thomas Hunt Morgan. Many a geneticist suspects that the impacts of cosmic rays also start mutations working in the germ plasm. When the National Geographic Society's balloon Explorer II made its record-breaking flight into the upper air last year, Dr. Victor Jollos of the University of Wisconsin sent jars of fruit flies up with it, outside the gondola. The insects died of cold, but offspring hatched from eggs...
...Association's Zoology Section, Dr. Huxley delivered an address on "Natural Selection and Evolutionary Progress." Natural selection has been subject to much criticism because it does not account for all aspects of evolution and because Darwin gave no emphasis to mutations (sudden changes in the germ plasm). Biologist Huxley sides neither with those who would explain everything by natural selection, nor with extreme proponents of the mutation theory such as Thomas Hunt Morgan. In the Huxley view the two factors complement each other. But: "Natural selection, in fact, though like the mills of God in grinding slowly and grinding...
...transmitted by a single gene. Resistance to the disease is a dominant character, and represses, but does not obliterate, the susceptibility factor whenever they occur together. A resistant individual mated to a susceptible one will have resistant offspring. But these offspring carry the susceptibility gene concealed in their germ plasm, and if they mate with susceptibles the second generation will be liable to cancer. The Slye mice show that not only inherited susceptibility but also some injury or chronic irritation is necessary for the malignant growths to appear. Dr. Slye has mice prone to cancer of the jaw which never...
...seen one. The chromosomes themselves in the fruit fly's germ cells are no larger than .00015 inch long, minute dots and streaks under the best microscopes. The chromosomes in the fly's salivary glands, however, are 70 times bigger than those in the germ-plasm, and two years ago Dr. Theophilus Shickel Painter of University of Texas took pioneer photographs of these tiny giants showing cross-bands. Then Dr. Bridges made such good photomicrographs of the salivary chromosomes that the crossbands marking gene locality came even more clearly to view, and the bands themselves were seen...